1. Field of the Invention
This invention relates to an image read-out and reproducing apparatus for carrying out read-out of an image recorded on an image information sheet such as a stimulable phosphor sheet and reproduction of the image thus read out on a recording sheet by use of the same scanning system.
2. Description of the Prior Art
Image read-out apparatuses for reading out an image recorded on a sheet by two-dimensionally scanning a light beam such as a laser beam on the sheet carrying the image recorded thereon, and by detecting light carrying the image information (for example, light reflected by the sheet, light transmitted therethrough, or light emitted thereby), which light is obtained when the sheet is exposed to the light beam, by use of a light detection means provided with photomultiplier or the like have heretofore been widely used as scanners for plate making, input apparatuses of a computer, and image readout apparatuses of a facsimile.
Also, when certain kinds of phosphors are exposed to a radiation such as X-rays, .alpha.-rays, .beta.-rays, .gamma.-rays, cathode rays or ultraviolet rays, they store a part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light, light is emitted by the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
As disclosed in U.S. Pat. Nos. 4,258,264, 4,276,473, 4,315,318 and 4,387,428 and Japanese Unexamined Patent Publication No. 56(1981)-11395, it has been proposed to use a stimulable phosphor in a radiation image recording and reproducing system. Specifically, a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet) is first exposed to a radiation passing through an object such as the human body to have a radiation image of the object stored thereon, and is then scanned with stimulating rays such as a laser beam which cause it to emit light in proportion to the stored radiation energy. The light emitted by the stimulable phosphor sheet upon stimulation thereof is photoelectrically detected and converted to electric image signals, and the radiation image of the object is reproduced as a visible image by use of the image signals on a recording material such as photographic film, a display device such as a cathode ray tube (CRT), or the like.
In the aforesaid radiation image recording and reproducing system, the radiation image stored on the stimulable phosphor sheet is read out by deflecting stimulating rays and scanning stimulating rays on the stimulable phosphor sheet in a main scanning direction in a radiation image read-out apparatus, simultaneously moving the stimulable phosphor sheet with respect to stimulating rays in a sub-scanning direction approximately normal to the main scanning direction, thereby scanning the overall surface of the stimulable phosphor sheet by stimulating rays, and photoelectrically detecting light emitted by the scanned portion of the stimulable phosphor sheet by use of a photodetector.
On the other hand, the image read out in the read-out apparatus such as the aforesaid radiation image read-out apparatus is reproduced as a visible image by, for example, scanning a light beam modulated in accordance with the image signals obtained by the read-out apparatus in the main scanning direction on a recording sheet which is being moved with respect to the light beam in the sub-scanning direction, and recording the visible image on the recording sheet. Therefore, in order to form the final visible image of the image, which was recorded on the image information sheet such as the stimulable phosphor sheet, on the recording sheet, it has heretofore been necessary to provide the reproducing apparatus for reproducing the image on the recording sheet, besides the read-out apparatus for reading out the image.
Particularly, in the case of the aforesaid radiation image recording and reproducing system, various attempts have been made in recent years to simplify the overall system as much as possible, to make the apparatus smaller as a whole and to reduce the manufacturing cost thereof. As one of such attempts, it has been proposed in Japanese Unexamined Patent Publication No. 58(1983)-184677 to form the conventional read-out apparatus, wherein scanning with a light beam is carried out, and the conventional reproducing apparatus, wherein scanning with a light beam is carried out, integrally with each other and to carry out image read-out and image reproduction by use of the same scanning system.
In the read-out and reproducing apparatus mentioned above, scanning must be carried out by use of a light beam of a predetermined optical amount in the course of image readout, and scanning must be carried out by use of a light beam modulated in accordance with the image information in the course of image reproduction. Accordingly, in the read-out and reproducing apparatus proposed in Japanese Unexamined Patent Publication No. 58(1983)-184677, a light modulator is moved into the light beam in the course of image reproduction, and is retracted from the light beam in the course of image read-out. In this case, a mechanism for moving the light modulator is necessary, and therefore the configuration becomes complicated.